Plasma polymerization of HMDSO films on dental materials: evaluation of surface characteristics and biofilm formation

Abstract

In the oral cavity, several species of microorganisms have been recovered from the dentition, tongue, cheeks, palatal mucosa and also from restorative materials and prostheses. Oral biofilm-associated diseases, such as periodontitis, peri-implant and candidiasis, may impact on quality of life. Potentially, each type of surface can be associated with the formation of different type of a biofilm, since the initial adhesion of microorganisms depends on the surface properties. Thus, surface modifications have been proposed to prevent or inhibit biofilm formation on biomaterials. In this context, this study will evaluate the effect of plasma-polymerized hexamethyldisiloxane (HMDSO) films on the surface characteristics of titanium, zirconia and acrylic resin, as well as on the biofilm formation on these surfaces. The films will be deposited by plasma enhanced chemical vapor deposition (PECVD) processing to obtain surfaces with hydrophobic or hydrophilic characteristics. Samples without treatment will be used as controls. The film characterization will be obtained through Fourier transform infrared (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM), contact angle and free energy measurements, X-ray photoelectron spectroscopy (XPS) and profilometry. For the biofilm formation, samples (10 X 2 mm) will be inoculated with Porphyromonas gingivalis for titanium and zirconia. Acrylic resin samples will be inoculated with Candida albicans. Microorganism suspensions will be spectrophotometrically standardized to a concentration of 1 X 107 cells mL-1. The biofilms of each microorganism will be evaluated by the number of colony forming units (CFU/mL) and XTT assay. The results of biofilm formation will be subjected to statistical analysis for further interpretation and discussion. (AU)